Radius belt with improved stiffness

ABSTRACT

A radius belt module suitable for large radius applications such as for spiral conveyors. The module has having an intermediate section including a cross rib having a corrugated portion extending along at least a portion of the length of the intermediate section. The intermediate section also has a web extending along the length of the intermediate section and disposed adjacent to the cross rib. The module has a first plurality of link ends extending outward from the intermediate section and having a transverse opening defined therein. The link ends are formed by a pair of spaced apart link members that are connected by a end portion. The link ends have a slot or opening defined therein from the top to the bottom of the module. The slot is bordered by the inside walls of the link members. The module also has a second plurality of link ends extending outward from the intermediate section in a direction opposite the first link ends. The second link ends have a transverse opening with an elongated shape. The link ends are formed by a pair of spaced apart link members that are connected by an end portion. The link ends have a slot or opening defined therein. The slot is bordered by the inside walls of the link members. The corrugated portion of the cross rib has a reach bar portion extending between first and second link ends and has a border portion disposed adjacent to the slot formed in the link ends.

FIELD OF THE INVENTION

This invention relates to conveyor belts and, more particularly, tomodular plastic conveyor belts formed of rows of plastic belt modulespivotally interlinked by transverse pivot rods. Modular conveyor beltsmay be straight running or capable of negotiating a curved path. Beltsthat are capable of turning are usually referred to as radius or turnbelts. The present invention pertains to radius belts.

BACKGROUND OF THE INVENTION

Radius belts are used in various applications for material handling aswell as for food processing. For processes with long dwell times, spiralconveyors are commonly used. It has been known to use modular beltsconstructed of steel for these applications. However, the wear on thebelts may produce blackening of the steel which contaminates thefoodstuff. Also, belts made of steel are typically heavy, expensive andcostly to repair. In response to some of these issues, it has been knownto use plastic belt modules with steel pivot rods. These belts addresssome of the drawbacks but still suffer from the blackening problems.Also, steel rods concentrate pulling forces in a radius belt at onesingle link, whereas plastic rods are usually flexible enough todistribute the load onto two or more of the outermost links of the belt.Accordingly, it is preferable to form a belt from all plasticcomponents.

Belts made entirely of plastic solve most of the above-describedproblems, but have the shortcoming of lower stiffness (lower modulus ofelasticity) and therefore do not allow large distances between wearstrips. Also, the reduced stiffness of plastic belts may create someproblems for radius belts. For example, when a radius belt rounds acurve, radial compression forces act on the module rows. These forcesmay cause compression of the plastic belts in this area. In addition,the bending stiffness of plastic belts is reduced. This reducedstiffness negatively affects the bending stiffness of the complete belt,if it is resting on support strips with large distances as common forspiral machines. Accordingly, there is a need for radius belts madeentirely of plastic materials that offer an improved stiffness withoutaffecting the ability of the belt to collapse in a curve. It is alsodesirable to have the stiffness as equal as possible over the full beltwidth. These belts have particular application for spiral conveyors andother very large radius applications.

SUMMARY OF THE INVENTION

The present invention meets the above-described need by providing aradius belt module having an intermediate section including a cross ribhaving a corrugated portion extending along at least a portion of thelength of the intermediate section. The intermediate section also has aweb extending along the length of the intermediate section and disposedadjacent to the cross rib. The module has a first plurality of link endsextending outward from the intermediate section and having a transverseopening defined therein. The link ends are formed by a pair of spacedapart link members that are connected by a end portion. The link endshave a slot or opening defined therein from the top to the bottom of themodule. The slot is bordered by the inside walls of the link members.The module also has a second plurality of link ends extending outwardfrom the intermediate section in a direction opposite the first linkends. The second link ends have a transverse opening with an elongatedshape. The link ends are formed by a pair of spaced apart link membersthat are connected by an end portion. The link ends have a slot oropening defined therein. The slot is bordered by the inside walls of thelink members. The corrugated portion of the cross rib has a reach barportion extending between first and second link ends and has a borderportion disposed adjacent to the slot formed in the link ends.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated in the drawings in which like referencecharacters designate the same or similar parts throughout the figures ofwhich:

FIG. 1 is a perspective view of an edge module of the present invention;

FIG. 2 is another perspective view of the edge module of FIG. 1;

FIG. 3 is a top plan view of the edge module shown in FIG. 1;

FIG. 4 is a bottom plan view of the module shown in FIG. 1;

FIG. 5 is a perspective view of the components of the belt of thepresent invention;

FIG. 6 is a perspective view of a belt of the present invention in astraight running condition;

FIG. 7 is a top plan view of the belt shown in FIG. 6;

FIG. 8 is a perspective view of a belt of the present invention shownrounding a curve in a “collapsed” condition; and,

FIG. 9 is a top plan view of the belt shown in FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, a module 20 has an intermediate section 23 extending from afirst edge 26 to a second edge 29 at the opposite side of module 20. Theintermediate section 23 extends in a direction transverse to thedirection of belt travel indicated by arrow 32. A first plurality oflink ends 35 extend from the intermediate section 23 in a direction ofbelt travel. The link ends 35 have a pair of outer walls 38, 41 defininga transverse thickness. A transverse pivot rod opening 44 extendsthrough the link ends 35 from wall 38 to wall 41. The opening 44 isround and sized to receive a pivot rod for connecting adjacent modules20. The link ends 35 have a proximal portion 47 that connects to theintermediate section 23, and the link ends 35 have a distal portion 50with an end wall 53. The first link ends 35 are formed with a pair ofspaced apart link members 62 and 65. The link members 62 and 65 may bemolded as solid plastic parts with rounded edges. The link members 62,65 may be disposed approximately parallel or at an angle in spaced apartrelation. The link members 62, 65 connect at a proximal end to theintermediate section 23. First ends 68, 71 of the link members 62, 65form the proximal portion 47 of link ends 35. The second ends 74, 77 ofthe link members 62, 65 extend to the distal portion 50. Each linkmember 62, 65 has an inner wall 83, 86 (FIG. 2) disposed on the sideopposite from outer walls 38, 41. The distal portion 50 has an innerwall 89 disposed opposite from outer wall 53. The intermediate section23 has a wall 88 (FIG. 4) at the proximal end of the link members andfacing in the direction of belt travel. The inner walls 83, 86, 88, and89 border a slot 92 that extends through the module 20 from the topsurface to the bottom surface.

A second plurality of link ends 94 extend from the intermediate section23 in the opposite direction from the first link ends 35. The first andsecond link ends 35 and 94 have spaces 99 between successive link ends.The link ends 35 and 94 on opposite sides of the intermediate section 23are offset such that adjacent modules 20 are capable of intercalatingsuch that the link ends 35 fit into the spaces 99 between link ends 94.Link ends 94 have a proximal portion 102 connected to the intermediatesection 23 and a distal portion 105 disposed opposite from the proximalportion 102. Link ends 94 have side walls 108, 111 forming a transversethickness. An elongated opening 114 extends through the link end 94 fromwall 108 to wall 111. As will be evident to those of ordinary skill inthe art based on this disclosure, the opening 114 is elongated as shownin FIGS. 1 and 2 so that when the belt negotiates a curve, the end ofthe modules 20 at the inside of the curve can “collapse” and the end ofthe modules 20 at the outside of the curve can “fan” out as will bedescribed in greater detail herein. When the modules are connected bythe pivot rod 59 (FIG. 5) to form a belt, the pivot rod 59 extendsthrough the round openings 44 and the elongated openings 114 inalternating fashion. As best shown in FIG. 4, the second link ends 94also include a slot 117 that is bordered by inside walls 200, 203 of thelink members 206, 209 on opposite sides and is bordered by wall 213 ofthe intermediate section 23 and the inside wall 212 of the distalportion 105 at the opposite end. One of the link ends 94 may be formedwith closed top and bottom surfaces 120, 121 that increase the strengthof the module 20.

As shown in FIGS. 1 and 3, the top surface 95 of intermediate section 23has an elongated approximately rectangular shape with a substantiallyuniform width W along its length between the first edge 26 and thesecond edge 29.

Referring to FIGS. 2 and 4, at the bottom of the module 20 theintermediate section 23 is formed by a cross rib 123 that extendssubstantially transverse to the direction of belt travel. The cross rib123 includes a substantially straight portion 124 at one end of themodule 20, which is toward the middle of the belt when the module 20 isassembled into a belt, and has a corrugated section 125 at the oppositeside where the module 20 forms the side of the belt. In the corrugatedsection 125, the cross rib 123 includes reach bar portions 129 thatextend between the link ends 35 and 94. The intermediate section 23extends from a bottom surface on the cross rib 123 to the top surface95. The top surface 95 is formed by a web 130 that is wider than thecross rib 123. The web 130 has approximately uniform width in thelongitudinal direction. The difference in width between the cross rib123 and the web 130 is smaller toward the middle of the module 20, andthe difference is greater toward the side edge 26 of the module 20because of the corrugation of the cross rib 123 to form reach barportions 129 and to provide space for collapsing at the inside of aturn.

Turning to FIG. 4, at the end of the module 20 toward side edge 26, thecross rib 123 forms reach bar portions 129 between successive links andforms a border portion 133 where the cross rib 123 forms a boundary ofthe slot 92. The thickness S₃ of the cross rib 123 between opposed linkmembers and the thickness S₂ of the reach bar 129 is preferably equal ornearly equal throughout the modules. However, this relationship ispossible only for certain collapse factors. For very small collapsefactors it may be necessary to reduce the thickness of the cross rib123. For example, the thickness of the cross rib 123 in the reach barportion 129 toward the side edge 26 may be reduced in order to providespace for the distal portion 50, 105 of the link ends 35, 94 to moveinward to collapse around the turns. The thickness S is measured fromside to side of the cross rib 123 (perpendicular to the lengthwisedirection of the cross rib 123) as it extends in serpentine fashiontoward the side edge 26 of the module 20 as shown in FIG. 4. Thethickness S₁ of the cross rib 123 in the border portion 133 may beincreased by altering the slot length L (FIG. 3). The thickness S₂ (FIG.4) of the cross rib 123 where it forms reach bar portion 129 betweensuccessive links is limited by the need for space for collapsing at theinside of turns. In order to strengthen the belt, the thickness S₁ ofthe cross rib 123 at the border portion 133 may be increased such thatit is greater than the thickness S₂ of the cross rib 123 at the reachbar portion 129.

The stiffness of the belt may further be increased by the arrangement ofthe link members 62, 65 and the link members 206 and 209. Link member 65on Link end 35 is disposed opposite from link member 206 on link end 94.The opposed link members 65, 206 are arranged such that they join intothe cross rib 123 in close proximity to further strengthen the belt. Thepoint where link member 62 connects to the cross rib 123 may also belocated in close proximity with the point where link member 203 connectsto the cross rib 123.

A bricklayed belt 300 (FIG. 6) may be formed from the components shownin FIG. 5. Module 20 may be connected to modules 310, 320 and 330 bymeans of the pivot rod 59. Side edge 26 of module 20 forms the edge ofbelt 300 and aligns with side edge 329 of module 330. Module 330 has anintermediate section 333 extending transverse to the direction of belttravel indicated by arrow 336. A first plurality of link ends 339 extendin a first direction. A second plurality of link ends 342 extend in asecond direction opposite to the first direction. The link ends 339 areformed in the same manner as described above in connection with linkends 35 and 94. Link ends 339 fit into the spaces 99 between link ends35.

Module 310 has a side edge 313 and an opposite edge 316 toward themiddle of the belt 300. AS shown, the top surface of the intermediatesection 314 is formed with a web 317 that is wider than the cross rib319. A first plurality of link ends 315 and a second plurality of linkends 318 extend in opposite directions from the intermediate section314. The first and second plurality of link ends 315 and 318 are formedin the manner described above in connection with link ends 35 and 94.

Module 320 has a side edge 323 and an opposite edge 326 disposed towardthe middle of the belt 300. As shown the top surface of the intermediatesection 324 is formed with a web 327 that is wider than the cross rib328. A first plurality of link ends 325 and a second plurality of linkends 366 extend in opposite directions from the intermediate section324. The first and second plurality of link ends 325 and 366 are formedin the manner described above in connection with link ends 35 and 94.

After the link ends of the four modules are intercalated and the pivotrod openings are aligned in the transverse direction, the belt 300 maybe assembled by inserting the pivot rod 59 through the aligned openings.As shown, the pivot rod 59 has an elongate substantially cylindricalbody 60 with a head 61 and a retaining ring 63 disposed at a first end64. The cylindrical body 60 terminates at a second end 66. As will beevident, to those of ordinary skill in the art, based on this disclosureother pivot rods may also be used to connect the modules. The pivot rod59 shown has the advantage that it can be inserted and removed from oneside of the belt 300. The retaining ring 63 prevents the pivot rod 59from sliding out of the modules in the axial direction and thereforeholds the modules together to form the belt 300.

Turning to FIGS. 6 and 7, the belt 300 is shown in a straight runningcondition where the modules are spaced apart equally on each side edge.The link ends of each module are disposed in the spaces between linkends of the adjacent module and the transverse pivot rod openings arealigned to receive the pivot rod 59. The modules are capable. of beingconnected by pivot rods 59 to form an endless belt 300 capable ofarticulating about a sprocket (not shown). As shown at the side edges onboth sides of the belt 300, the link ends disposed at the side edges ofthe belt do not have to extend very far into the openings of adjacentmodules at the side edges of belt 300 when the belt is in the straightrunning condition.

Turning to FIGS. 8 and 9, the belt 300 is shown in the “collapsed”condition as it negotiates a curve. On the right hand side of thefigure, the modules are collapsed as they would be around the insidecurve of a turn. As shown in FIG. 9, the link ends at the edge of themodule corresponding to the inside of the curve are collapsed and extendas far as possible into the openings between adjacent link ends. Inorder for the link ends to extend as far as possible into the adjacentspaces, the cross rib 123 is corrugated at the side edges. As shown onthe left hand side of FIG. 8, the opposite edge of the modules “fans”out such that there is a maximum distance between the link ends ofadjacent modules.

While the invention has been described in connection with certainembodiments, it is not intended to limit the scope of the invention tothe particular forms set forth, but, on the contrary, it is intended tocover such alternatives, modifications, and equivalents as may beincluded within the spirit and scope of the invention as defined by theappended claims.

1. A belt module comprising: an intermediate section including a crossrib having a corrugated portion extending along at least a portion ofthe length of the intermediate section and the intermediate sectionhaving a web extending along the length of the intermediate section andadjacent to the cross rib; a plurality of first link ends extendingoutward from the intermediate section and having a transverse openingdefined therein, the link ends having a pair of spaced apart linkmembers and having an end portion connecting the link members, the linkends having a slot defined therein; and a plurality of second link endsextending outward from the intermediate section in a direction oppositethe first link ends, the second link ends having a transverse openingwith an elongated shape defined therein, the link ends having a pair ofspaced apart link members and having an end portion connecting the linkmembers, the link ends having a slot defined therein; and, wherein thecorrugated portion of the cross rib has a reach bar portion extendingbetween first and second link ends and has a border portion disposedadjacent to the slots formed in the link ends.
 2. The belt module ofclaim 1, wherein the slot comprises an opening extending from a topsurface of the link end to the bottom surface of the link end.
 3. Thebelt module of claim 1, wherein the cross rib includes a substantiallystraight portion.
 4. The belt module of claim 3, wherein thesubstantially straight portion is disposed toward the middle of the beltwhen the modules are intercalated.
 5. The belt module of claim 1,wherein at least one of the link members of the first plurality of linkends connects with the intermediate section in close proximity to whereat least one of the link members of the second plurality of link endsconnects with the intermediate section.
 6. The belt module of claim 1,wherein the border portion of the cross rib has a thickness that isgreater than the thickness of the reach bar portion.
 7. The belt moduleof claim 1, wherein the thickness of the cross rib between opposed linkmembers is approximately equal.
 8. The belt module of claim 1, whereinthe thickness of the cross rib between opposed link members is reducedtoward the belt edge.
 9. The belt module of claim 1, further comprisingat least one link end having closed top and bottom surfaces.
 10. Thebelt module of claim 1, wherein the web is wider than the cross rib. 11.The belt module of claim 1, wherein the difference between the width ofthe web and the width of the cross rib at the side edge is greater thanthe difference between the width of the web and the width of the crossrib near the edge opposite from the side edge.
 12. A modular belt,comprising: a plurality of belt modules having an intermediate sectionincluding a cross rib having a corrugated portion extending along atleast a portion of the length of the intermediate section and a webextending along the length of the intermediate section and adjacent tothe cross rib; a plurality of first link ends extending outward from theintermediate section and having a transverse opening defined therein,the link ends having a pair of spaced apart link members and having anend portion connecting the link members, the link ends having a slotdefined therein; and a plurality of second link ends extending outwardfrom the intermediate section in a direction opposite the first linkends, the second link ends having a transverse opening with an elongatedshape defined therein, the link ends having a pair of spaced apart linkmembers and having an end portion connecting the link members, the linkends having a slot defined therein; wherein the corrugated portion ofthe cross rib has a reach bar portion extending between first and secondlink ends and has a border portion disposed adjacent to the slots formedin the link ends; and, a plurality of pivot rods disposed throughaligned transverse openings in intercalated belt modules.
 13. The beltmodule of claim 12, wherein the cross rib includes a substantiallystraight portion.
 14. The belt module of claim 13, wherein thesubstantially straight portion is disposed toward the middle of the beltwhen the modules are intercalated.
 15. The belt module of claim 12,wherein at least one of the link members of the first plurality of linkends connects with the intermediate section in close proximity to whereat least one of the link members of the second plurality of link endsconnects with the intermediate section.
 16. The belt module of claim 12,wherein the border portion of the cross rib has a thickness that isgreater than the thickness of the reach bar portion.
 17. The belt moduleof claim 12, wherein the thickness of the cross rib between opposed linkmembers is approximately equal.
 18. The belt module of claim 12, whereinthe thickness of the cross rib between opposed link members is reducedtoward the belt edge.
 19. The belt module of claim 12, furthercomprising at least one link end having closed top and bottom surfaces.20. The belt module of claim 12, wherein the web is wider than the crossrib.
 21. The belt module of claim 12, wherein the difference between thewidth of the web and the width of the cross rib at the side edge isgreater than the difference between the width of the web and the widthof the cross rib near the edge opposite from the side edge.
 22. A methodof forming a radius belt, comprising: providing a plurality belt moduleshaving an intermediate section including a cross rib having a corrugatedportion extending along at least a portion of the length of theintermediate section and a web extending along the length of theintermediate section and adjacent to the cross rib; a plurality of firstlink ends extending outward from the intermediate section and having atransverse opening defined therein, the link ends having a pair ofspaced apart link members and having an end portion connecting the linkmembers, the link ends having a slot defined therein; and a plurality ofsecond link ends extending outward from the intermediate section in adirection opposite the first link ends, the second link ends having atransverse opening with an elongated shape defined therein, the linkends having a pair of spaced apart link members and having an endportion connecting the link members, the link ends having a slot definedtherein; wherein the corrugated portion of the cross rib has a reach barportion extending between first and second link ends and has a borderportion disposed adjacent to the slots formed in the link ends;intercalating adjacent modules such that the link ends of a first moduleextend into the spaces between the link ends of an adjacent secondmodule, the modules being aligned such that the transverse openings ofthe first link ends align with the transverse openings of the secondlink ends of the adjacent module; inserting pivot rods through thealigned transverse openings of adjacent modules to form an endless beltcapable of articulating about a sprocket.